


Summoning Sickness

by goldenteaset



Category: Fate/Grand Order, Fate/stay night & Related Fandoms
Genre: (For the good of Ritsuka's funds more-or-less), Cosplay, Don't eat the mapo tofu Ritsuka, Gen, Gilgamesh (Fate) Being an Asshole, Look at this crap Sanson has to deal with, Mild Solomon spoilers, POV Multiple, Polyamory, Possessive Behavior, Scheming, Shippy Gen, Video Game Mechanics, one-sided Gilgamesh/Saber
Language: English
Status: Completed
Published: 2019-01-11
Updated: 2019-01-11
Packaged: 2019-10-08 11:16:15
Rating: Teen And Up Audiences
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 2,952
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/17385464
Author URL: https://archiveofourown.org/users/goldenteaset/pseuds/goldenteaset
Summary: Ritsuka Fujimaru has a terrible sickness, and the only cure is an elaborate role-playing metaphor. (In Gilgamesh's opinion, anyway.)





	Summoning Sickness

**Author's Note:**

> Hallo! There are too many Servants coming out this year, so I wrote this slightly-self-indulgent one shot to keep my rolling in check. ^^; Maybe it'll help others, too!
> 
> There's a slight reference to "Pharaoh and Physician", but you don't need to read that to enjoy this fic. 
> 
> Disclaimer: I don't own FGO.

“Oh, how unfortunate,” Gilgamesh says dryly, as yet another bowl of mapo tofu glows to life in Chaldea’s Summoning Circle. “You’ve been dealt yet another bad hand, I see.”

Ritsuka—the mongrel with the bad luck in question—lets out the longest, saddest sigh in existence and slumps to her knees. “What is _with_ this month?! Nothing but failed Summons, all the time!” 

“Mm.” Gilgamesh bites the inside of his cheek, forcing his mirth down. (The first time this happened, _he_ was the culprit.) “Who were you so insistent on acquiring today? That flowery mage, or the ‘me’ with the exposed thighs?”

Another world-weary sigh. “Both of them.”

“…I see.” He gives her an appraising look. “If you’re so desperate to see me in a Caster’s attire, you need only beg.”

“Uh-huh.” Ritsuka scowls down at the single Saint Quartz in her hand as if it murdered her puppy.

 _She will reconsider in time._ Gilgamesh gives the Summoning room a passing glance, noting that the jade-colored circuits on the black walls and the elaborate details of the Summoning Circle are still in working order. (But then, he already knew that.) “Well, it seems your Servant luck has run out for this year.” He pauses, attempting to think of a reassuring phrase. “But a new year is on the horizon.”

“…I guess,” Ritsuka says, hanging her head so low she may as well be sprawled on the ground. Her trembling hands grope about for the foul-smelling mapo tofu. “Maybe this will taste good…”

This will not do. A plan—possibly three or more—must be made and put into action, and soon.

\---

“Mozart?! _K_ _nock_ before entering my room, you wretch!” Sanson yells, as someone materializes opposite the glass door of the shower. “Must I throw you out like a stray cat again?”

But of course he must.

Wiping his dripping face with the back of his hand, Sanson prepares to turn off the hot spray easing his muscles after a long week of saving the world. (Literally. He still isn’t quite sure how he managed it, but Solomon was split in two by his blade. Marie finished off his familiar—or was that the true culprit? He’s too exhausted to recall.)

Regardless, humanity is saved. And now a certain wretched composer has more free time than he knows what to do with.

“I will warn you once more,” he growls, his bones weary all over again. “Leave, or else I—”

“—Ah, so you _can_ raise your voice after all, mongrel.” That is decidedly _not_ Mozart’s voice. It’s close, but far deeper and regal.

That voice can only be Gilgamesh’s.

It is now of the utmost importance that Sanson find a towel. The King of Heroes isn’t to be kept waiting. _Why is he even here? My room is hardly fit for royalty—even Marie finds it too similar to Master’s._

But that isn’t important. When dealing with royalty, one must be punctual. He makes himself presentable as quickly as he can, toweling off and tugging on his undergarments and shirt in record time. It’s difficult with his skin still being damp, but he manages.

“My apologies,” he says as he shuts the shower door behind him. “How may I be of service, King of Heroes?”

Gilgamesh nods in approval. “Our Master requires your assistance, mongrel.”

“And I would be glad to help.” Sanson places a hand over his heart. “Do you know what she needs?”

“An intervention. For you see, she insists on wasting valuable Saint Quartz even when the results disappoint her. She has even threatened to consume _mapo tofu_ , of all things!” He tilts his head to one side and scowls. “As such, my mongrel needs to be brought to heel.”

Sanson opens his mouth to reprimand Gilgamesh for his choice of words—then reconsiders. This is one of the few Servants to have bonded intensely with Ritsuka Fujimaru, and who on top of that is a rather possessive king; this _would_ bother him. _And in truth her Summoning bothers me as well. Ritsuka was being careful with her Saint Quartz before…but lately she has no restraint to speak of. What if she overexerts her Magic Circuits and cannot protect herself in battle?_

“You see?” Gilgamesh says, as if he can read Sanson’s mind. Just like a certain Pharaoh, perhaps he can.

“…Yes.” Sanson lifts his head proudly. “If nothing else, our Master needs to calm her mind. So what do we do, King of Heroes?”

His lips curl into a sly grin. “As it happens, Saber and I have a plan—one of many, in fact, but this one seems the most entertaining for all involved. We simply require you to accompany it. I shall explain…”

Once Sanson hears the plan in full, he finds he quite likes it. Ritsuka has certain weak spots, and this hits all of them with expert precision. One might even call it unfair. _Dare I ask who invented this scheme in the first place? Hmm…perhaps such things are best left unanswered._

“I’ll do my best, for Master’s sake.”

Gilgamesh chuckles. “Excellent.”

\---

Gilgamesh can’t resist a short laugh. “You mustn’t sulk, mongrel; it’s unbecoming!”

Ritsuka somehow manages to scoff while keeping the thermometer in place. An impressive feat for a mongrel…but then she’s brimming with great deeds. Sometimes. At the moment, not so much.

It’s quite a sight to behold: Chaldea’s last Master is lying in bed with her arms stubbornly folded across her chest and a thermometer sticking out of her mouth like a post-meal toothpick. Her eyes flick around the room before finally settling on Gilgamesh. It seems she suspects him to be the instigator of all this. (She knows him too well.)

Sanson looks to Gilgamesh uncertainly. “Shall I turn down the lights, King of Heroes?”

“Check our Master’s temperature first.” This game needs to be _somewhat_ realistic, after all. “Or have you forgotten your calling,  _physician_?”

Sanson shakes his head, his brows pinched in annoyance. “Don’t be ridiculous. I would never!” So saying, he bends down and plucks the thermometer from Ritsuka’s lips with care. The glass glints like silver in the brilliant overhead lights. His eyes darken; he’s a more convincing actor than expected. “…I see. Yes, it’s as I feared.”

Ritsuka props herself up on her elbows, tense with concern. “Is it serious?”

“That it is.” A threatening pause for effect. “Master, I’m afraid you have Summoning Sickness.”

“I have what now?” Ritsuka giggles nervously. “That—that sounds fake. I trust your other diagnoses, Sanson, but not this one! C’mon, tell me what’s up.”

Gilgamesh’s eyebrows rise up in surprise. “Hmm. I assumed you would understand, but apparently not.”

Humanity’s last Master lifts her chin in defiance. “I don’t have Summoning Pox or whatever. I just have bad luck right now!”

Sanson scratches his cheek and smiles secretively. “You’re unconvinced? Then perhaps my assistant will change your mind.”

“Your 'assistant'?” Ritsuka’s mercurial attitude shifts from rebellion to curiosity. “Who?”

“Good afternoon,” Saber says, as the sliding doors part for her like a crowd before a royal procession. “I am Sanson’s assistant today.” She pauses, her white kitten heels ceasing to click on the linoleum floor. “A- _hem._ Please close your mouth, Master.”

“Okay,” Ritsuka says, utterly stunned.

“…And further, you mustn’t stare at me that way.”

“You ask the impossible,” Gilgamesh purrs. “This attire suits you, Saber.”

Saber’s glare is so stern it could tear his atoms asunder. The nurse’s cap atop her golden-blonde head assists the image, truly giving her a feeling of strictness. “Hold your tongue, King of Heroes.”

“Oh, very well.” It isn’t _his_ fault she insisted on wearing practical attire for this venture and instead became a vision. Nor is she to blame. _She could wear a ragged cloth and transform it into a gown…_

The King of Knights' gaze turns elsewhere, softening in an instant. “Master? Is something wrong?” Her blue nurse gown and white apron sway as she walks toward the bed, hinting at a white petticoat beneath. 

“No; you just look beautiful, Saber,” Ritsuka pipes up, her hand half-outstretched as if to touch the lovely nurse before her.

Saber glances down at the clipboard in her hand; is that a flush blooming on her cheeks? “O-Oh. Thank you, Master.” Her regal mien returns in a flash. “In any event—I fear you have all the symptoms of Summoning Sickness: wasting Saint Quartz as soon as you acquire it, listlessly mooning about the Summoning Circle, a distinct sense of melancholy when your attempts fall short…and most damningly of all, you do so _every day_ without fail.”

Each time Saber taps at her clipboard, Ritsuka further curls in on herself. If she cringes any harder, she could turn into a tortoise. “I…well…yes, that’s exactly what happens,” she admits. Her hands inch toward her eyes to block her Servants' piercing gaze. “But it’ll be fine. I’m sure my luck changed!”

“ _No_ ,” Sanson snaps in a slightly louder pitch than usual.

That gets the intended reaction. Ritsuka furrows her brows and looks ready to interject; yet she manages to nod instead. “You’re right. That won't last.”

“Indeed,” Gilgamesh says, “even with one such as myself at your side, Golden Rule seems ineffective when it comes to Summoning.”

(It still rankles that it took _precisely_ one year for Saber to make her appearance. On the other hand, he and Ritsuka bonded over their shared woe.)

“Okay, okay.” After a sullen pause, Ritsuka perks up. “But—wait, you said there was a cure—”

“There is,” Sanson assures her. “Simply put, you require something to keep you from using Saint Quartz.”

“That makes sense, I guess. But…” Ritsuka leans forward, the little hamster wheels in her head ever-so-slowly beginning to turn. “…What could be better than Saint Quartz?”

For the first time, Gilgamesh feels a faint chill of doubt. _Good grief, she truly is falling ill._ _Will this plan be enough? Or will that Asterios mongrel need to trap her in his Labyrinth after all?_ It’s quite unpleasant, to think of this scheme crumbling to dust after he deigned to make an effort.

Sanson chuckles, the quiet warmth piercing through the smothering cloak of silence that surrounds them. “Your sense of time is off-balance again, Master,” he chides her gently.

“Not even a month ago,” Saber adds, “you were excited for something that was on the horizon—something that invigorated you more than Christmas itself.”

The wait is agonizing. _Let this be as we suspected—_

“Oh!” Ritsuka jolts up, all atremble with enthusiasm. “That’s right. Valentines!”

At last, there it is.

Saber’s smile has a hint of sharpness to it now. “Precisely, Master. Thus, we have an ultimatum.”

Ritsuka gasps. “You don’t mean—?”

“If you continue to willingly succumb to your Summoning Sickness,” Gilgamesh picks up, smirking as Ritsuka’s joy begins to crumble, “we will cancel Valentines…and White Day for good measure.”

Where seconds prior his Master was joyful and radiant, now there is only a cloud of shock and loss. “Wait…no…there’s no way! I—I planned out everyone’s gifts, they’re all sketched out. Archer and I were just getting the ingredients ready!”

Sanson runs a nervous hand through his silver hair. “‘Everyone’s gifts’, you say…? You are too generous, Master. And yet, I would treasure whatever you offered me.” The many Grails inside him are proof of that.

Ritsuka nods, looking ready to wilt. “I know…thank you…”

Gilgamesh throws back his head and laughs. “Indeed! You _should_ have offered me tribute last year, mongrel. It would be utterly dismal to be empty-handed yet again.” He extends a hand, allowing Ritsuka to admire their elegant construction. “And I would reward you handsomely in return…”

“Really? Er, thanks.”

 _Hmm. Perhaps I should have phrased that differently. “And I would adore you” would have far more power behind it._ Still, the point has been made, judging by that slight flush to his Master’s cheeks.

There’s an unexpected pause. A certain someone should have spoken up by now.

Gilgamesh looks to Saber, whose eyes are hidden by her bangs. “Saber?” he asks as gently as he can manage. “What do you make of all this?”

“—A moment, King of Heroes. I felt a bit strange just now.” She takes a deep breath and visibly steels herself.

Here comes the true test. The one who Ritsuka Fujimaru spent countless Saint Quartz on in relentless toil now steps forward to offer her ultimatum.

“It truly is a shame.” Saber sighs and looks off to the side, the very picture of a melancholy knight searching for her lost lady. “I confess I am preparing something for you as well. If you were to miss it simply because of a few Saint Quartz…that would be heartbreaking.”

Moments pass as the words sink in.

Then—at long last—Ritsuka falls into Saber’s waiting arms, burying her face in Saber’s shoulder. “I’m really sorry, everyone!” Her cries are a bit muffled. “I’ll do my best to keep my Summoning in check, I promise!”

“We understand,” Saber murmurs, her hand trailing through Ritsuka’s hair. She flicks a glance at Gilgamesh and Sanson in turn. “Isn’t that so?”

“Of course,” Sanson replies, coming over to awkwardly pat their Master’s shoulder. Displays of affection are not his forte…though he’s making an attempt. “My apologies, but I must be off; Marie and D’eon invited me to tea.”

Ritsuka lifts her head and gives him a teary smile and thumbs up.

With a crisp bow Sanson sets off on his next appointment. He’ll inform Marie of what went on, no doubt. That is fine—there were many plans waiting in the wings, and one of them involved that French queen and her countless tea parties. _She will be pleased by Sanson’s success and reward him in kind._

Gilgamesh saunters over to Saber, keen to reclaim a certain amount of his mongrel’s affection. (He acknowledges Saber’s and certain mongrels’ claim to Ritsuka as well, naturally. In situations like this, monogamy is hardly ideal. Even so…he is Ritsuka’s king. That carries a certain privilege.)

Saber’s expression has a hint of disappointment when she sees him coming, but she still allows Gilgamesh to take Ritsuka off her hands. “Treat her with care,” she whispers in his ear before striding out the door—presumably to change.

 _Naturally. Who does she take me for, a cur in heat?_ Shaking his head, he turns back to the matter at hand. “There, there,” he croons, possessively drawing Ritsuka to his chest and wrapping his arms around her trembling body. “Valentine’s will occur as planned—you’re an honest mongrel, and you keep your word. A point needed to be made.”

His mongrel sniffles an affirmative, her hands hovering at his hips as if unsure where to go next. “There’s one thing I need clarification on, though,” she says, lifting her head to turn red-rimmed eyes up to his face.

“Then speak.”

She worries her lip a bit before acquiescing to his order. “Um, what would happen if I already Summoned someone earlier?”

“I would be quite surprised.” Suspicion slithers through his mind. “…Wait a moment. When you said your luck had ‘changed’…you meant you Summoned a new Servant?”

“Yep!” And she’s obnoxiously unrepentant about it. 

There is but one thing to say in response: “ _Who?_ ”

His question is answered by a voice booming and rolling like thunder down the hall. “Physician! What glad tidings. To think you would bear witness to my splendor again!”

 _I should refuse mana transfer from you for a month, mongrel!_ With great effort Gilgamesh calms himself. Just because Ozymandias is an arrogant royal with (he must admit) an appealing body does _not_ mean that Ritsuka dares replace him. That threat may belong to his Caster self. And that is a threat he has no intention of confirming.

“…Good day, Pharaoh.” Sanson is quick to react—but then perhaps he’s used to the unexpected by now. “Has Mash shown you around Chaldea?”

“Yes, and she told me of this festival called Valentines as well. I look forward to receiving confections worthy of my status!” Ozymandias’ laughter rings out as if celebrations have already begun.

Gilgamesh sighs and grins down at Ritsuka. “Well, then, it seems you have a fitting trial to accompany your success. I shall enjoy watching you struggle, mongrel!”

Ritsuka sighs and gives him a half-hearted punch to the shoulder; it barely registers as a tickle. “Just wait and see, my King. I’ll keep my promise and show you how much I care for everyone!”

He decides to laugh and say nothing. Sometimes it rankles him to share. Even with Saber.

“Let us see how that physician is faring against your new Servant,” he says, taking Ritsuka by the hand and leaving her room behind.

“Sure thing,” she says, the familiar heat of her Command Seals tickling his palm. “Maybe we can convince Saber to wear that outfit again, while we’re at it!”

Occupied as she is, she doesn’t notice the Gate of Babylon snatching up her remaining Saint Quartz and tickets.

Thus, the third plan is enacted: cut the problem at the root, and then later reward Ritsuka for upholding her promise by returning her meager funds. _While this plan is the easiest to perform, the one we chose was indeed more entertaining. To think a nurse uniform effects Ritsuka so! Perhaps in private I shall deign to wear one myself from time to time..._

“My King?” his mongrel peers up at him curiously. “Did you think of a joke?”

“You’ll understand soon enough,” Gilgamesh says with a chuckle, as the golden portal behind them closes without a sound.   

**Author's Note:**

> Thanks for reading! Feedback is appreciated. :D


End file.
